Cylindrospermopsis raciborskii (Cyanobacteria) exudates: Chemical characterization and complexation capacity for Cu, Zn, Cd and Pb
Cylindrospermopsis raciborskii is a cosmopolitan and potentially toxic planktonic Cyanobacteria that produces and exudes copious amounts of dissolved organic materials. This organism dominates the eutrophic reservoir Barra Bonita (Brazil), where it normally blooms throughout the year. This investiga...
| Published in: | Water Research |
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| Main Authors: | , , , , |
| Other Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Elsevier B.V.
2014
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| Subjects: | |
| Online Access: | http://repositorio.unifesp.br/handle/11600/37394 https://doi.org/10.1016/j.watres.2013.10.025 |
| Summary: | Cylindrospermopsis raciborskii is a cosmopolitan and potentially toxic planktonic Cyanobacteria that produces and exudes copious amounts of dissolved organic materials. This organism dominates the eutrophic reservoir Barra Bonita (Brazil), where it normally blooms throughout the year. This investigation focused on the characterization of such exudates analyzing their capacity to complex copper, zinc, lead and cadmium through the determination of ligand concentration (C-L) and conditional stability constant (logK'mL), as well as elemental composition (C, H, N and S), the content of carbohydrates, proteins, lipids and dissolved organic carbon (DOC). the dissolved organic material was fractionated into 3 molecular weights (>30 kDa; 30-10 kDa; 10-3 kDa) and each fraction was analyzed. the results showed that in the >30 kDa and 30-10 kDa fractions carbohydrates dominate over proteins and lipids. Different CL and logK'mL were obtained for the different molecular weight fractions of the excreted organic materials, suggesting high diversity of ligands. in the >30 kDa, there were more complexing sites (CL) for Cu, but higher affinity (K') for Zn. in the 30-10 kDa fraction, the higher C-L was for Cd, but the greatest affinities were for Cu and Zn. in the 10-3 kDa fraction, higher C-L was obtained for Cd and Zn, while Cu and Cd had the highest strengths of association. in the environment, such diversity of ligands and strengths of association can result in a displacement of metals weakly bound to the EOM, and increase metal buffering capacity of the environment, supporting higher metal inputs before toxic effects are detected in the biota. (C) 2013 Elsevier B.V. All rights reserved. Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Univ Fed Sao Carlos, Dept Chem, BR-13565905 Sao Carlos, SP, Brazil Univ Fed Sao Carlos, Dept Bot, BR-13565905 Sao Carlos, SP, Brazil Mem Univ Newfoundland, Dept Ocean Sci, St John, NF, Canada Universidade Federal de São Paulo, BR-11060001 São Paulo, Brazil Univ Santa Cecilia, Dept Ecotoxicol, BR-11045907 São Paulo, Brazil Universidade Federal de São Paulo, BR-11060001 São Paulo, Brazil FAPESP: 2005/51263-5 CNPq: 302837/20124 Web of Science |
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